Acoustic device



Feb. 9, 1932. J. D. SEABERT ACOUSTIC DEVICE Filed Oct. 15, 1950 Patented Feb. 9, 1932 UNITED STATES PATENT OFFICE JOHN D. SEAIBEBT, OF DAYTON, OHIO, ASSIGNOB TO GENERAL MOTORS RADIO CORPORA- TION, OF DAYTON, OHIO, A CORPORATION OF OHIO ACOUSTIC DEVICE Application filed October 18, 1980. Serial No. 488,385.

This invention relates to an acoustic device and more particularly to the driving mechanism thereof.

An object of the invention is to change the magnitude of the force applied to the diaphragm from that of the force supplied by the driving mechanism. This has been accomplished by providing a connecting link arranged at an acute angle to the direction of the normal movement 0 the diaphragm, said connecting link including a flexible portion and an inflexible portion so that the magnitude of the force applied to the connecting link is different from the magnitude of the force applied to the diaphragm.

Another object of this invention is to provide a connecting link having a flexible portion and an inflexible portion. This has been accomplished by forming a portion of the link into a substantially U-shaped cross sectional area whereby the flexing of said formed portion is prevented.

Another object of this invention is to reduce the cost of the connecting driving mechanism without sacrificing its performance. This has been accomplished by providing a single flexible connecting link which is used instead of the conventional leverage mechanism used in changing the magnitude of the force in the conventional speakers. As is well known this leverage mechanism requires usually at least three movable parts and a support for the one that is fulcrumed. From this it can be readily seen that the number of 7 parts has been reduced, without sacrificing eficiency of the device. This results in a saving in material, labor, time, parts and costs.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings, wherein a preferred embodiment of one form of the present invention is clearly shown. In the drawings:

Fig.1 represents across section through an acoustic device.

Fig. 1a is a sectional view taken on the line lav-14 of Fig. 1.

. Fig. 2 is a sectional view, drawn to a larger scale and taken on the line 22 of Fig. 1.

Fig. 3 is a sectional view taken on the line 3-3 of Fig. 1, showing a cross-sectional view of the connecting link.

Fig. 4 discloses a fragmentary view of the connecting link, taken in the direction of the arrow 4 in Fig. 3.

Fig. 5 is a diagrammatic view of the connecting link in two positions the imaginary and the resulting or true movements of four important points being shown in approximately the right direction.

Referring to the drawings, a permanent magnet 12, secured to a frame or a radio chassis (not shown) in any suitable manner, supports a housing 14, which is fastened to the permanent magnet 12 and pro erly spaced therefrom by the studs 16, threa ed at one end into the permanent magnet 12 as at 17. The free lengths of the studs 16 project through the interposed spacing members 18 while the locking nuts 20 are threaded upon the studs 16 and secured against loosening by the lock washers 22.

The housing 14 is provided with a flanged portion or rim 2A which serves as a support for a tone damping felt cone 26, which rests against the inner conical surface of the housing 14, a flared portion 28 of a reproducing cone or diaphragm 30 and a ring-like clamping member 32 of suitable form, which cooperates with the rim 24 to clamp the flared portion 28 of the diaphragm 30 and the stretched outer periphery of the felt cone 26. A plurality of screws 34, projecting through holes of the ring 32, the flared portion 28 of the diaphragm 30, the felt cone 26 and the rim 24 of the housing 14, receives locking nuts 36 which are secured by the lock washers 38, thus supplying the necessary pressure to produce enough friction between the supported parts 32, 30 and 26 and the supporting rim 24 to hold these members in a relatively rigid relation.

of the cross bar 60 is adjusta-bly fastened tothe brackets 48 and 50 respectively by screws 63 as clearly shown in Fig. 1a; he cross bar itself is actually twisted in its midd e portion for allowing the armature 58 to oscillate be tween the said innermost ends and47 of the :pole pieces 44 and 46, respectively, so as to actuate the diaphragm through the connecting'link 64. The armature58 is immersed in a magneticlfield such that the force acting on one end of the armature is opposite in direction to the force acting upon'the other end when the speech coil is energized. This causes. the armature 58 to oscillate about the pivot in one plane only, but in either direction, depending upon the directionof flow h of the exciting'current in the coils. The different polarities on the ends of the armature 58 aid each other in oscillatingthe armature.

It must be clearly understood that the above described driver as well as the diaphragm with the housing could be of any other well known type, each of these members per se not forming part of my invention.

In order to have the proper acoustic repro duction it is sometimes necessary to change the relative magnitude-of the force moving the diaphragm with respect to the magnitude ofthe force moving the armature, so as to produce the desired ratio of amplitudes between thehigh and low frequency audio tones or signals as is well known to. those skilled in the art. Magnitude of force as used in the specification and claims refers to the distance through which the driving end of the armature is displaced or the distance through f movement of the point D due to a certain re- "sistance of the diaphragm against moving 'in'. horizontal direction to either side, the other vice thatproduces this desired change'in the Y which 'the' apex of the cone travels as the casemaybe. v I The following description relates to a demagnitude of the foregoing. magnitude of forces that represents my invention.

Biveted to or otherwise secured to the armature 58 is the one flexible end .62 of a connecting link 64, the other flexible end 66 of the link 64 is secured to the center ofa spider 68, cemented or otherwise secured to holdall of these parts in a relatively fixed position. The end 66 may be attachedtothe part of certain length bent into a U-shaped or semi-circular or any other shape which best insures inflexibility over the desired length. The twonarrow flexible ends 62 and 66 of the link 64 may each be provided with a slot 76 to make these ends even more flexible.

Referring now to Fig. 5, the point Econp stitutes thepivot for the armature 58 while the two pole pieces 44 and 46 are partly shown insection. The flexible ends a and b as well as theinflexible portion 0 are shown in full lines in the one, and in dot-an'd-dash lines in the other position. The imaginary and the. true .or resulting movements of four points A, B, C and D will now be analyzed.

For thesake of analysis the are through which the end of the armature moves will be considered a path. Then the horizontal com-' ponent R is only left, which is transmittedto the point B as K if the flexible end a were rigid or inflexible. Since this enda is flexa. The result is a movement R that is transmitted to the point C as K by the inflexible portion 0. -As, however, the point D of the flexible end I) can move in horizontal direction only, the transmitted motion K causes the point C to follow an evasive path'or curve,

movementof the point C is therefore R that is transmittedto the point D as K by the imaginary inflexible end b. The end 6 however,

which gives the component K The resulting T nents. -The one counteracts the horizontal is a'lateral component, due tothe flexing of the end 7), started at C and taken up by the flexing end Z) itself. The resultant in the i diagram, however, is R in horizontal direc- W ment of the diaphragm. V r

The diagram thus shows" that the disposition of the described connecting memberbetween the armature and the diaphragm'produces the, desired change in magnitude of the force applied to the link to that applied to the diaphragm. T

.tion and constitutes the true horizontal move- It must b'e understood, however, that in the -1 four diagrams shown, all components that are affected by the flexibility of the two ends a and b can be drawn in an approximate direction only, as the influence of flexibility does not readily allow a statical solution.

A different ratio of the change of the magnitude applied to the link to that supplied to the diaphragm can easily be made by simply changing the angle that the link forms with the axis of the cone or by changing the flexibility of the two ends a and b, either by changing the width or length of the slots 66 or the thickness of the flexible ends, or by changing the length of the two ends a and 1).

While the form of embodiment of the present invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

1. In an acoustic device, a movable diaphragm for reproducing sound, a driving mechanism for actuating said diaphragm and a link mechanism connecting said driving mechanism and said diaphragm, said link mechanism comprising a flexible member arranged at an acute angle with respect to the direction of the normal movement of the diaphragm, said link being so arranged as to flex upon being actuated, thereby changing the magnitude of the force delivered with respect to the force applied.

2. An acoustic device comprising in combination, a frame, a diaphragm mounted in said frame, a driving mechanism and a flexible link for connecting the driving mechanism to the cone, said link being arranged at an acute angle with respect to the direction of movement of said diaphragm so as to change the magnitude of the output force of the link with respect to the magnitude of the input force due to the flexing and to the angular arrangement of the link.

3. An acoustic device comprising in combination, a frame, a diaphragm mounted in said frame, a driving mechanism and a flexible link for connecting the driving mechanism to the diaphragm, said link delivering a force of a different magnitude from that applied to it due to the flexing of the link.

4. An acoustic device for reproducing electrical impulses comprising in combination, a frame, a cone diaphragm mounted in said frame, a driving mechanism for actuating said diaphragm in response to electrical impulses, and a flexible connecting link for connecting the driving mechanism to the diaphragm, said link being arranged at an acute .ingle with respect to the axis of said diaphragm so as to change the magnitude of the force delivered from that applied, said change resulting from a flexing of the link, and a flexible member for connecting the apex of the cone to the frame whereby the cone is actuated substantially alongits axis.

5. A connecting link for connectin the driving mechanism of an acoustic device to its diaphragm, said link including a slotted flexible portion and an inflexible portion.

6. A mechanism for connecting the driving mechanism of an acoustic device to the diaphragm, said connecting mechanism including a flexible link that alters the magnitude of a force applied to the link with respect to the magnitude of the force delivered.

7. 'A connecting link for connecting the driving mechanism of an acoustic device to its diaphragm, said link including a flexible portion and an inflexible portion having a U-shaped cross-sectional area.

8. A connecting link for connecting the driving mechanism of an acoustic device to its diaphragm, said link including an inflexible portion havin a U-shaped cross-sectional area and a exible portion having a rectangular cross-sectional area.

9. An acoustic device for reproducing electrical impulses comprising in combination, a frame, a cone diaphragm mounted in said frame, adriving mechanism for actuating said diaphragm in response to electrical impulses, a connecting device including a rigid part arranged at an acute angle with respect to the axis of said diaphragm, said rigid part having one end connected to the diaphragm and a part being flexibly arranged with respect to said rigid part for connecting the other end thereof to said driving mechanism, and a flexible member for connecting the apex of the cone to the frame whereby the cone is actuated substantially along its axis.

10. An acoustic device for reproducing electrical impulses comprising in combination, a frame, a cone diaphragm mounted in said frame, a driving mechanism for actuating said diaphragm in response to electrical impulses, a connecting device including a rigid part arranged at an acute angle with respect to the axis of said diaphragm, said rigid part having one end connected to said driving mechanism and a part being flexibly arranged with respect to said rigid part for connecting the other end thereof to said diaphragm, and a flexible member for connecting the apex of the cone to the frame whereby the cone is actuated substantially along its axis.

11. An acoustic device for reproducing electrical impulses comprisng in combination, a frame, a cone diaphragm mounted in said frame a driving mechanism for actuating said diaphragm in response to electrical impulses, a connecting device including a rigid intermediate part arranged at an acute angle with respect to the axis of said diaphragm, a part being flexibly arranged with respect to said intermediate part for connecting the driving mechanism to one end of said intermediate link and a part for connecting the diaphragm to the other end of said intermediate part so as to deliver a different mag nitude of force to the diaphragm through said intermediate part thanshall be imparted from said driving mechanism'to said intermediate part, and a flexible member for connecting the apex of the cone to the frame Wherebythe cone is actuated substantially along its axis.

12.. An acoustic deviceaccording to claim 91in Which'the rigid part is of U-shaped cross sectional area and the part Which connects-the oneend of said rigid part Withthedriving mechanismv of rectangular crosssectional shape.

13. An acoustic device according to claim 10 in, which the rigid part is of U-shaped cross sectional area and the part Which connects the one end of said rigid part with the diaphragm is of rectangular cross-sectional shape. 1

In testimony whereof I hereto 'atfix my signature. v

.JOHN D. SEABERT. 

